A Practical Introduction to eBay's Web API

eBay's API is more powerful than ever, and offers plenty of functionality for creating powerful and interesting applications. However, getting up to speed can be a bit daunting. Tim Stevens will get you started.

Like this article? We recommend

Over the past few years, many of the most popular sites on the web have begun
to give developers windows into those sites' inner workings. With new
computer-based security threats appearing every day, Yahoo!, Google, and eBay
have all gone to great lengths to open the door to developers. Where the
interfaces for the first two are interesting but tend to be focused on creating
simple apps, eBay's Developers Program presents a very powerful and
feature-rich toolset focused on creating usable applications. But with that
power comes some extra complexity not found in the other two APIs.

Purpose

Before we dig into the details, let's take a quick look at the purpose
of the eBay toolset, and how you get started with it. Whereas the APIs you
can use to access the Google and Yahoo! sites seem to be angled toward creating
cool, free apps, eBay's API is a rather different beast, focused on creating
applications that will, in some way, turn a profit.

Because of this focus, releasing an application that utilizes the eBay API "in
the wild" (the live production eBay.com auctions) is a complicated process.
Google and Yahoo! are perfectly happy to let you search their data and do with
it what you will (to a degree). But because the eBay API allows you to insert
and bid on auctions, performing transactions that involve real-world money,
a formal certification process has been created.

eBay has created a developer membership program with yearly dues and fee-based
technical support, with the higher levels receiving extended usage rights to
the production eBay environment. Individuals can get limited free access and
10,000 API calls per month, but any large-scale deployment of an application
will require someone to cough up some dough and move up to one of the higher
levels.